Tertiary-butoxycarbonyl (Boc) – A strategic group for N-protection/deprotection in the synthesis of various natural/unnatural N-unprotected aminoacid cyanomethyl esters
available 4M HCl in 1,4-dioxane solution (2–4 equiv); acetonitrile, 0 °C, 2–4 h was a suitable condition. This condition was generalized and successfully applied to a variety of alkyl, alkynyl, aryl, heteroaryl, benzyl, azido, spiro amino acid cyanomethylesters irrespective of the nature of the amine (primary or secondary) and the distance between the amine and ester group to achieve final deprotected
Cleavage of a carbon–fluorine bond by an engineered cysteine dioxygenase
作者:Jiasong Li、Wendell P. Griffith、Ian Davis、Inchul Shin、Jiangyun Wang、Fahui Li、Yifan Wang、Daniel J. Wherritt、Aimin Liu
DOI:10.1038/s41589-018-0085-5
日期:2018.9
Cysteine dioxygenase (CDO) plays an essential role in sulfur metabolism by regulating homeostatic levels of cysteine. Human CDO contains a post-translationally generated Cys93âTyr157 cross-linked cofactor. Here, we investigated this CysâTyr cross-linking by incorporating unnatural tyrosines in place of Tyr157 via a genetic method. The catalytically active variants were obtained with a thioether bond between Cys93 and the halogen-substituted Tyr157, and we determined the crystal structures of both wild-type and engineered CDO variants in the purely uncross-linked form and with a mature cofactor. Along with mass spectrometry and 19F NMR, these data indicated that the enzyme could catalyze oxidative CâF or CâCl bond cleavage, resulting in a substantial conformational change of both Cys93 and Tyr157 during cofactor assembly. These findings provide insights into the mechanism of CysâTyr cofactor biogenesis and may aid the development of bioinspired aromatic carbonâhalogen bond activation. Engineered variants of cysteine dioxygenase containing a halogen-substituted tyrosine analog provide insights into the process of CysâTyr cross-link formation and indicate that the enzyme can catalyze oxidative cleavage of a carbonâfluorine bond.
Mechanism of the AppA<sub>BLUF</sub> Photocycle Probed by Site-Specific Incorporation of Fluorotyrosine Residues: Effect of the Y21 p<i>K</i><sub>a</sub> on the Forward and Reverse Ground-State Reactions
作者:Agnieszka A. Gil、Allison Haigney、Sergey P. Laptenok、Richard Brust、Andras Lukacs、James N. Iuliano、Jessica Jeng、Eduard H. Melief、Rui-Kun Zhao、EunBin Yoon、Ian P. Clark、Michael Towrie、Gregory M. Greetham、Annabelle Ng、James J. Truglio、Jarrod B. French、Stephen R. Meech、Peter J. Tonge
DOI:10.1021/jacs.5b11115
日期:2016.1.27
proton is completely transferred in the transitionstate leading from light to dark adapted AppA. A large solvent isotope effect of ∼ 6-8 is also observed on the rate of dark state recovery. These data establish that the acidity of Y21 is a crucial factor for stabilizing the light activated form of the protein, and have been used to propose a model for dark state recovery that will ultimately prove useful
Neuropeptide-2 receptor (Y-2R) agonists and uses thereof
申请人:Conde-Knape Karin
公开号:US20070135351A1
公开(公告)日:2007-06-14
Provided herein are neuropeptide-2 receptor agonists of the formula (I):
as well as pharmaceutically acceptable salts, derivatives and fragments thereof, wherein the substituents are as those disclosed in the specification. These compounds, and the pharmaceutical compositions containing them, are useful for the treatment of diseases such as, for example, obesity and diabetes.
The present invention relates to novel bicyclic and tricyclic nucleoside and nucleotide analogues as well as to oligonucleotides comprising such elements. The nucleotide analogues, LNAs (Locked Nucleoside Analogues), are able to provide valuable improvements to oligonucleotides with respect to affinity and specificity towards complementary RNA and DNA oligomers. The novel type of LNA modified oligonucleotides, as well as the LNAs as such, are useful in a wide range of diagnostic applications as well as therapeutic applications. Among these can be mentioned antisense applications, PCR applications, strand displacement oligomers, as substrates for nucleic acid polymerases, as nucleotide based drugs, etc. The present invention also relates to such applications.